The World Wide Web is the distributed system of communication and information transfer over the Internet made possible by the widely supported hypertext transfer protocol (HTTP). Client side web browsers implement the client side of the HTTP protocol and utilize Uniform Resource Locators (URLs) to locate a specific resource on the World Wide Web. The syntax and semantics of URLs, the formalized information for location and access of resources on the Internet, is specified in RFC 1630, a document written by the URI working group of the Internet Engineering Task Force. at http://www.w3.org/Addressing/URL/Overview.html. The URL allows resource locations to be described by a simple string. URLs can point to resources on a local server or they can point to resources on an external server. In the following disclosure, an external link is a link whose URL has a domain name that differs from the URL used to retrieve the current document.
Web pages are written in HyperText Markup Language (HTML), the publishing language of the World Wide Web. The HTML 4.01 Specification, found at http://www.w3.org/TR/REC-html40/ defines the HyperText Markup Language (HTML). Web pages generally contain both internal links and external links. It is useful to indicate to the client that a link is an external link so the client will know that linking to that URL will require leaving the current server. In HTML pages, webmasters sometimes manually highlight external URLs by manually coding adornments such as images around links to external URLs as a visual warning to the user that they are leaving the current site. For example a common image used for this purpose is a small image of a globe to the right of the link. The image is presented as a visual clue to the user that the link leaves the current site. The webmasters also commonly have external links open in a new window. However it would be simpler to place the responsibility for providing such visual clues onto the client software, since the client software has enough information to determine this.
There is therefore a need for a method for using client software to provide a visual or other indication that a link on a web page is an external link.
U.S. Pat. No. 5,924,104 discloses a method and apparatus for displaying interdocument links in a computer system. A document is parsed to identify links. The identified links are parsed to identify interdocument links and the identified interdfocument links are displayed in a first presentation style. Other links are displayed in a second presentation style.
Patent Cooperation Treaty publication 0033213A consists of a system spidering a web document and summarizing the document structure and links in a new document. The system does not provide an indication in the original web document.